1. Field of the Invention
The present invention relates to a musical tone synthesizing apparatus which is suitable for synthesizing a percussion instrument tone.
2. Prior Art
Conventionally, Japanese Patent Laid-Open Publication No. 63-40199 discloses the apparatus capable of synthesizing the sound of non-electronic musical instrument by use of a simulation model which simulates the tone-generation mechanism of non-electronic musical instrument. In case of the wind instrument, when the resonance state is established between the non-linear vibration of the read which is produced by the breath pressure applied thereto and the vibration of the compression wave of air which is produced in the resonance tube by the non-linear vibration of the reed, the musical tone is sounded from the wind instrument. Herein, the musical tone synthesizing apparatus for the wind instrument can be embodied by using the non-linear amplifier which simulates the reed operation and bi-directional transmission circuit simulating the tube through which the compression wave of air propagates.
FIG. 1 shows the known musical tone synthesizing apparatus capable of generating the synthesized percussion instrument tone. In FIG. 1, a closed-loop is constructed by an adder 1, a delay circuit 2 and a filter 3. This closed-loop functions as the resonance circuit corresponding to the resonance system of the percussion instrument. Herein, delay time of the delay circuit 2 and transmission-frequency characteristic of the filter 3 are determined in response to the resonance characteristic and delay characteristic of the percussion instrument to be simulated.
In order to generate the percussion instrument tone from this musical tone synthesizing apparatus, an impulse signal containing a plenty of different frequency components is applied to the adder 1. Such impulse signal is delayed by the delay circuit 2, attenuated by the filter 3 and then fed back to the adder 1. As described heretofore, the impulse signal is repeatedly circulating the closed-loop. As a result, the adder 1 can output the signal wherein the envelope is attenuated in lapse of time and each of its frequency components is varied in lapse of time. Thus, it is possible to synthesize the musical tone which is similar to the sound of percussion instrument.
According to the physical analysis, the tone-generation mechanism of the percussion treatment can be represented by the physically continued vibration medium (e.g., cymbal can be represented by one metal plate). When sounding the percussion tone, the vibration including a plenty of different vibration frequencies is effected on the vibration medium in circulating manner. In the case where the vibration including many kinds of frequency components propagates through the vibration medium, the frequency components interferes with each other so that each frequency component must be modulated in the actual play of the percussion instrument. Such phenomenon becomes remarkable in case of the cymbal. However, the conventional musical tone synthesizing apparatus is not designed to reproduce the above-mentioned mutual interference between the frequency components of the vibration to be produced. Thus, there is a problem in that the conventional apparatus cannot synthesize the musical tone which realizes the actual percussion instrument tone and whose tone color is full of variety like the rear percussion instrument.